Type synthesis and application of a class of single DOF parallel mechanisms with one constraint couple

This paper presents a design method for single Degree of Freedom(DOF) parallel mechanisms with one constraint couple based on screw theory. A new equation is proposed for this case. A group of parallel robots containing three identical legs and mixed legs is calculated with this approach. Then the sum of motion modes for this kind of structures is also determined. One feasible mechanism is chosen to gain flexibility in a reconfigurable parallel robot with a special trajectory planning as an example.